This invention relates to magnetic devices for spreading sheet metal stacks of laminations in general and more particularly to an improved device of this nature.
Magnetic devices for spreading a stack of magnetizable individual sheet metal laminations with a central hole, in which the individual laminations in the stack are guided by a prismatic mandrel which fits in the central hole, are known. In the known magnetic spreading devices for such lamination stacks, which are deposited on pallets with upright centering mandrels, vertically supported permanent spreading magnets, which spread the individual laminations apart in fan-like fashion over their axial range of action, are used. In order to spread apart the upper end regions of the lamination stacks guided by the centering mandrels, the magnets are disposed about the outer periphery of the end regions. This is done to permit removal, individually, of the respective uppermost individual laminations, so that the respectively uppermost individual lamination can be taken off and be moved to further processing stations located elsewhere. This is necessary, for instance, in the case of stored circular blanks for electric machines or apparatus for feeding the individual laminations to stamping presses.
In this kind of spreading device, a vertical centering mandrel is required for every lamination stack to guide the spread apart individual laminations. The mandrel determines the maximum height of the lamination stack and must have an outside diameter adapted to the size of the central hole of the individual laminations. In addition, the upright magnetic spreading device must be adapted to the outside diameter of the lamination stack, so that it surrounds the lamination stack with a definite uniform spacing. Since this spreading device surrounds the lamination stack in the upper region, access to the respective spread-apart uppermost individual laminations is made more difficult and, because of the mentioned arrangement, more space is required in the surroundings of each lamination stack for mounting the spreading device.
It is an object of the present invention to provide a magnetic spreading device in which the centering mandrels for the individual lamination stacks are unnecessary, the space required around each lamination stack can be kept smaller, and the height of the lamination stacks can be chosen freely according to the respective requirements. Optionally, the spreading device can also be used at the same time as transporting means at least for parts of the stacks.